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Pyruvate dehydrogenase kinase 1 (PDHK1) and carbonic anhydrase IX (CAIX) are some of the most hypoxia-inducible proteins associated with tumors, implicated in glucose metabolism and pH regulation, respectively. They both appear to be necessary for model tumor growth, and their high level of expression in human tumors predicts poor patient outcome. Another thing they have in common is that hypoxia not only induces their expression but also their enzymatic activity. This work therefore simultaneously targets these two hypoxia-inducible proteins either pharmacologically or genetically in vitro and in vivo, leading to decreased cancer cell survival and significantly slower model tumor growth. It also suggests that CAIX and PDHK1 are important for cells originating from a colorectal primary tumor, as well as from its metastasis. Moreover, our analysis reveals a unique relationship between these two HIF-1 target genes. In conclusion, the attributes of PDHK1 and CAIX predict them to be promising targets for the design of new, specific inhibitors that could negatively influence tumor cell proliferation and survival, or increase efficacy of standard treatment regimens, and at the same time avoid normal tissue toxicity.

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BACKGROUND: Although imatinib is the standard treatment for chronic myeloid leukaemia, not all patients reach complete cytogenetic remission (CCR) and most maintain detectable disease at the molecular level. We investigated whether a vaccine targeting the BCR-ABL-derived p210 fusion protein was an active and specific immunotherapy. METHODS: We recruited 16 patients who had chronic myeloid leukaemia (with the b3a2 fusion point of p210), stable residual disease, a minimum treatment of 12 months of imatinib or 24 months of interferon alfa, and no further reduction of residual disease for at least 6 months preceding enrollment. They were given six vaccinations with a peptide vaccine derived from the sequence p210-b3a2 plus molgramostim and QS-21 as adjuvants (CMLVAX100) before assessment of immunological and disease response, which included detecting amounts of b3a2 transcripts by standardised quantitative real-time reverse-transcriptase PCR. RESULTS: Of ten patients on imatinib, nine started CMLVAX100 having had a median of 10 months' stable cytogenetic disease (median 10% Philadelphia-chromosome-positive metaphases), whereas one started in stable CCR. All patients' cytogenetic responses improved after six vaccinations, with five reaching CCR. Notably, three of these five patients also had undetectable amounts of b3a2 transcript (BCR-ABL:beta2 microglobulin ratio <0.00001). Six patients on interferon alfa treatment with a median of 17 months' stable residual disease (median 13% Philadelphia-chromosome-positive cells) were also vaccinated. All but one had improved cytogenetic responses, and two reached CCR. Overall, we recorded peptide-specific delayed-type hypersensitivity (in 11 of 16 patients), CD4 cell proliferation (13 of 14 assessed), and interferon gamma production (five of five assessed). INTERPRETATION: Addition of CMLVAX100 to conventional treatment in patients with chronic myeloid leukaemia might favour further reduction of residual disease and increase the number of patients reaching a molecular response.

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BACKGROUND AND OBJECTIVE: Fludarabine monophosphate (FAMP) is a purine analog with specific therapeutic activity in B-cell chronic lymphocytic leukemia (CLL). Its current use as front-line therapy of CLL is still a matter of debate both because of the controversial results of the clinical trials so far reported and because of the toxicity profile of the drug. In order to contribute to clarifying the possible role of FAMP, we report a retrospective analysis of the results obtained with the purine analog in CLL patients in different phases of the disease. DESIGN AND METHODS: Forty-seven patients affected by advanced CLL, 36% untreated, 31.9% relapsed and 31.9% resistant, were treated with FAMP 25 mg/m2/day, either for 4 days every 3 weeks in 29 cases, or for 5 days every 4 weeks in 18. The median number of FAMP cycles was 6 (range 2-11). Response was defined according to total tumor mass (TTM) score reduction and toxicity was expressed according to WHO grading criteria. The median follow-up of the series was 13 months from the beginning of FAMP therapy. RESULTS: Out of 47 evaluable patients the response rate was 74.4%, with 34% complete response (CR). The overall response rate was 94%, 80% and 46.6% in untreated, relapsed and resistant cases, respectively; a significantly higher number of responses was associated with no previous treatment and number of FAMP cycles. Fifty-three percent of all cases and 58.8% of untreated ones did not experience any toxicity. Treatment-related side effects were mainly autoimmune phenomena in untreated patients and infectious complications in treated ones. One heavily pre-treated patient died because of neurologic complications. Median time to re-treatment was18 months (range 1-30) and was influenced by age and previous treatment. The overall median survival was 35.7 months with a significantly higher proportion of surviving cases among RAI 0-II stages, responders and patients receiving more than 5 FAMP cycles. INTERPRETATION AND CONCLUSIONS: The present report confirms the high efficacy of FAMP in previously pre-treated cases with acceptable toxicity and encourages its use as front-line treatment provided that the results of randomized trials demonstrate its superiority over conventional chemotherapy. The possible development of autoimmune phenomena should, however, be considered seriously.

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BACKGROUND: Fas antigen (Ag) has recently been identified as the putative surface molecule capable of transducing apoptotic signals into cells. Alterations in the expression of proto-oncogene bcl-2 have been implicated in the regulation of apoptosis. MATERIALS AND METHODS: By employing a monoclonal antibody to bcl-2 protein (124 clone) and to Fas Ag (UB2 clone) the expression of these molecules was analyzed at flow cytometry on bone marrow (BM) and peripheral blood (PB) samples from patients suffering from different lymphoid and myeloid leukemic diseases (27 acute non-lymphocytic leukemia [ANLL]; 14 acute lymphocytic leukemia [ALL]; 19 B-cell chronic lymphocytic leukemia [CLL]; 2 Ph1+ chronic myeloid leukemia [CML]; one CD8+ T-cell chronic lymphoproliferative disorders). Results were compared with those observed on normal PB leukocytes and BM B-cell precursors from patients with non-neoplastic hematological disorders. RESULTS: Fas Ag was constitutively expressed by both monocytes and neutrophils, while lymphocytes expressed bcl-2 with no difference between B and T cell subsets. Interestingly, bcl-2 expression was always absent on neutrophils. When dealing with ANLL patients, a relatively low bcl-2 and high Fas Ag phenotype characterized subtypes with granulocytic (M2) or promyelocytic (M3) differentiation. This observation was confirmed in a small number of patients for whom bcl-2 levels were quantified as antibody binding capacity (ABC) in molecules/cell. Leukemic cells from patients with ALL constitutively expressed bcl-2, the pattern of this expression being quantitatively lower than that of immature B-cell precursors. Finally, high bcl-2 and low Fas Ag expression represented a crucial part of the B-cell CLL immunophenotype. CONCLUSIONS: Although based on a small number of patient and control samples, our results suggest that bcl-2 and Fas Ag are coordinately expressed on normal PB leukocytes. Fas Ag is expressed at low levels on B-CLL cells, generally considered long-surviving cells. The relatively lower bcl-2-expression detected in both M2 and M3 subtypes may explain, at least in part, the higher remission rates obtained in these forms of ANLL than in other less differentiated morphological variants.

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